4 L16H battery bank buss bar?

SOMF

Any comments or recommendations, the circuit breaker is a bussman 181060F Hi-Amp waterproof DC model.

jonr

Has it ever been settled if bus bars create excessive strain on the terminals?   

SOMF

I hadn't thought of that, I wouldn't expect the short bar to heat up enough to expand and contract but the batteries themselves certainly could. I don't have any reason to use the copper bars except to eliminate 4 crimped connectors. It's been recommended to use 2awg cables to the CC which is the max size for the FM60 but I believe the cables to the inverter are 2/0 so should the short jumpers be 2awg or 2/0? 

Marc Kurth

jonr said:

Has it ever been settled if bus bars create excessive strain on the terminals?   

That seems to depend upon whom you ask............There seem to be folks here who are convinced that bus bars will damage batteries.

I would NOT use bus bars on portable/marine/RV/industrial vibration applications for exactly that reason. I have been personally involved with many 8 to 10 year old projects out there with bus bar interconnects on stationary banks. I have not yet seen one crack or loose/leaking battery terminal because of them.

Please note that I am NOT saying that it has never happened to anyone else! Just MY experience with the hundreds of battery banks that I have been involved with.

Typically, I see bus bars on 2v cells in longer strings, but they can also provide a good solution for high current loads where 4/0 causes an unacceptable voltage drop.

I seriously learn a lot from this site, so I am always ready to learn more from people with differences experience than mine!

Marc

Edit to add: We DO follow the manufacturers requirement of 1/4" to 3/8" MINIMUM space between batteries which is smart for thermal purposes anyway!

jonr

I would worry about what the batteries are sitting on and how much it expands/contracts with temperature.  For example, polyethylene moves a lot.  But it's also fairly slippery, which can minimize strain.  Also what the expected temperature range is.

Marc Kurth

Worst case temperature swings in my world would be remote sensing and RF systems deployed in the southwest deserts and mountain sites from Maine to Colorado.

Typically, the batteries are on wood or steel shelves or standing on a concrete slab. Bus bars are standard procedure for the interconnects. Slots instead of holes are used to make it easier to put the batteries in a "relaxed" position before applying the torque wrench. Remember that airspace between batteries is always provided.

Some systems have the batteries standing vertically, others are horizontal mount. Keep in mind that my personal experience is narrowly limited to AGM's only, but I don't know how battery type would have a lot of influence on the subject.

Are other people actually seeing stress damage from bus bars?

Marc

ramloui

Will there be stress on battery terminals if a 10" copper bus bar goes from 0 F to 100 F? Yes.

How much stress? Well, how much stress can a 0.017" increase in length over 10" cause?

http://www.engineeringtoolbox.com/linear-thermal-expansion-d_1379.html

If you think this is still too much, then maybe an expansion loop as what is used in long piping runs:

Just a thought.

Louis R.

SOMF

Good information, it's only 2 batteries in a bank x 2 for 870ah so I'll just go with cable instead of the buss. Thanks for all of the guidance!

ramloui

Actually, I was suggesting that the stress can't be that much... Anyway, cable works great too, that's what I have.

Have a good day!